1、 More recently,so-called"heliographs"have been used to relay military signals in a similar way.
更近一点例子是，“日光反射信号器”一直通过类似的方式传递军事信号。
来源:
2、 More recently, so-called"heliographs"have been used to relay military signals in a similar way.
更近一点例子是，“日光反射信号器”一直通过类似的方式传递军事信号。
来源:
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